Re: [PATCH v9 12/13] mm: smaps: Report arm64 guarded pages in smaps
From: Kees Cook <hidden>
Date: 2020-03-13 00:00:35
Also in:
linux-arm-kernel, linux-fsdevel, lkml
On Wed, Mar 11, 2020 at 07:26:07PM +0000, Mark Brown wrote:
From: Daniel Kiss <redacted> The arm64 Branch Target Identification support is activated by marking executable pages as guarded pages. Report pages mapped this way in smaps to aid diagnostics. Signed-off-by: Daniel Kiss <redacted>
Reviewed-by: Kees Cook <redacted> -Kees
quoted hunk ↗ jump to hunk
Signed-off-by: Mark Brown <broonie@kernel.org> --- Documentation/filesystems/proc.txt | 1 + fs/proc/task_mmu.c | 3 +++ 2 files changed, 4 insertions(+)diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt index 99ca040e3f90..ed5465d0f435 100644 --- a/Documentation/filesystems/proc.txt +++ b/Documentation/filesystems/proc.txt@@ -519,6 +519,7 @@ manner. The codes are the following: hg - huge page advise flag nh - no-huge page advise flag mg - mergable advise flag + bt - arm64 BTI guarded page Note that there is no guarantee that every flag and associated mnemonic will be present in all further kernel releases. Things get changed, the flags maydiff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index 3ba9ae83bff5..1e3409c484d1 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c@@ -668,6 +668,9 @@ static void show_smap_vma_flags(struct seq_file *m, struct vm_area_struct *vma) [ilog2(VM_ARCH_1)] = "ar", [ilog2(VM_WIPEONFORK)] = "wf", [ilog2(VM_DONTDUMP)] = "dd", +#ifdef CONFIG_ARM64_BTI + [ilog2(VM_ARM64_BTI)] = "bt", +#endif #ifdef CONFIG_MEM_SOFT_DIRTY [ilog2(VM_SOFTDIRTY)] = "sd", #endif-- 2.20.1
-- Kees Cook